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CLINICAL

The mechanism by which the burn injury was sustained is extremely important (i.e., flame, chemical, electrical, etc.) as this influences the management. A major point is to determine if the victim was confined in an area where fire was present, as this strongly suggest an inhalation injury. What was the duration of exposure to the agent (flame, chemical, electrical, etc.)

Other important points include the patient's tetanus immunization status as well as the components of the history outlined by the mnemonic AMPLE:

A - Allergies M - Medications (including over the counter and Aspirin) P - Past Medical History / Previous Illness L - Last meal or beverage consumed E - Events preceeding injury (HPI).

Pediatric Burns:

Unforturnately, burns in children may result from abuse. Medical personnel must consider abuse as a cause of burns in all children, as many as 10% of abuse cases involve burns. (See chapter on Pediatrics, Child Abuse).

Components of the history that should raise suspicion include: Multiple stories of how injury was sustained, injury attributed to a sibling or unwitnessed, injury that is incompatible with the developmental level of the child.

Characteristics of the burn that should raise suspicion include pattern burns that suggest contact with an object, cigarette burns, stocking glove or circumferential burns, burns to genetalia or perineum.

If there is a suspicion of abuse contributing to the burn injury, it must be reported to the appropriate agency!

Medical personnel must also be aware that burns resulting from abuse or neglect may also be seen in the geriatric population.

Physical:

Burns are classified by depth, type and extent of injury.

Burn Depth:

Burn depth is described as first, second or third degree.

A  first degree burn is one that involves only the epidermis. This tissue is erythematous and often painful. This tissue will blanch with pressure. Minimal tissue damage is seen with this injury. The classic example of this type burn is sunburn (see chapter on Sunburn for more details and mangement).

Second degree burns, also referred to as partial thickness burns, involve the epidermis and portions of the dermis. They often involve adnexal structures, such as sweat glands and hair follicles but enough of these structures are preserved that epithelium lining them can proliferate and allow for re-growth of the skin.

The burned area characteristically has blisters and is very painful. With deep second degree burns, edema that accompanies the injury, plus decreased blood flow in the tissue, can lead to conversion to a full thickness burn, if not properly managed.

Third degree burns, or full thickness burns, are characterized by charring of the skin or a translucent white color, with coagulated vessels visible below. The area is insensate but the patient complains of pain, usually from the surrounding second degree burn. As all of the skin tissue and structures are destroyed, healing is very slow and often associated with extensive scarring as epithelial cells from the skin appendages are not present to repopulate the area.

Burn Types: (Please see Causes discussion below.)

Extent of Burns:

The more body surface area involved in a burn, the greater the morbidity, mortality and difficulty in management. There is a tendency for EMS personnel to overestimate the extent of the burn and for ED personnel to underestimate the burn.

The palmar surface of an individual represents 1% of the body surface area. A simple method to estimate burn extent is to use the patients palmar surface to measure the burned area. Only second and third degree burns are measured in calculating the burn area.

Another quick method is to use the Rule of Nines to estimate the extent of burn injury.

For small children, the head represents a greater portion of the body mass than adults. Lund and Browder first described a method for compensating for the differences and the Lund and Browder Chart is used to calculate Body Surface Area (BSA) in children. If the chart is unavailable, one can estimate body surface area and adjust for age, as follows

- In children < 1 year, the head is 18% and each leg is 14% - The torso and arms represent the same percentages as in the adult - For each year over 1, add 1/2 percent to each leg and decrease the percent for the head by 1%, until adult values are reached.

• Based upon extent and depth, emergency physicians can determine the severity of the burn injury and whether the patient requires transfer to a burn center. These criteria for a burn center admission have been developed by the American Burn Association:

• Full thickness (3rd Degree)burns over 5% BSA

• Partial thickness (2nd Degree) burns over 10% BSA

• Any full thickness or partial thickness burn involving critical areas, such as burns to the face, hands, feet, genitals or perineum, or burns to the skin over any major joint, as these have significant risk for functional and cosmetic problems.

• Circumferential burns of thorax or extremities.

• Significant chemical injury, electrical burns, lightning injury, co-existing major trauma or presence of significant pre-existing medical conditions

• Presence of Inhalational Injury

Causes:

• Flame Burns:

  Contact with open flame causes direct injury to the tissue. In addition, the flame may ignite clothing. While natural fibers tend to burn, synthetic fibers may melt or ignite, adding a contact type burn component to the injury.

• Contact Burns:

  Contact burns result from direct contact of the tissue with a hot object. The burn injury is confined to the point of contact. Examples are burns from cigarettes and tools, such as soldering irons or cooking appliances.

• Scalds:

  Scalds result from contact with hot liquids. An important point is that the more viscous the liquid and the longer the contact with the skin, the greater the damage. Accidental scalds often show a pattern of splashing, with the burns separated by patches of uninjured skin. In contrast intentional scalds such as child abuse often involve the entire extremity, in a circumferential fashion, with a line that marks the liquid surface.

• Steam Burns:

  Steam burns are most often seen in industrial accidents or from automobile radiators. These burns produce extensive injury, due to the high heat carrying capacity of steam and the dispersion of the pressurized steam and liquid. Inhalation of steam can actually cause thermal injury to the distal airways of the lung.

  Inhalation of hot gas normally does not injure distal airways, as the heat exchange capacity of the upper airway is excellent. The upper airway is at risk, in this situation, for thermal injury and subsequent occlusion due to edema. Distal airway injury is more likely due to the direct effects of the products of combustion on the mucosa and alveloli.

• Electrical Burns:

  Electrical burns produce heat injury by passing through the tissue. Ignition of clothing may produce some flame burn, but the majority of injury is deep to the skin.

• Flash Burns:

  A subset of flame burns, these are seen with the rapid ignition of a flamable gas or liquid. The body parts involved are those that are exposed to the agent when it ignites. Areas covered by clothing are usually spared. There may be facial involvement, but if this type injury takes place outside, then the risk for inhalational injury is low. A careful examination of the airway is indicated.

  A classic example of this type of injury is the person who pours gasoline on a trash or leaf fire to increase the flame and is burned by the fireball that follows.